JP2002165751A - Fluoresent endoscopic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means for eliminating a moire in a fluorescent endoscopic device that occurs in an image to be obtained when a fluorescent image propagated by an image guide is photographed. SOLUTION: A fluorescent endoscopic device in which a fluorescent image Zk generated from a biological tissue 1 and received an irradiation of an excitation light Le is allowed to be propagated to its edge 21B, and the fluorescent image Zk thus propagated to the edge 21B is formed into an image by a means to produce fluorescent images 30 through spectral distribution over mutually different three wavelength areas and photographed by highly sensitive photographing elements 41, 42 and 43 where a phase plate 81 such as a quartz crystal birefringent plate, or the like, is placed between a switching mirror 39 and a dichroic mirror 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent endoscope apparatus, and more particularly, to a fluorescent endoscope apparatus for spectrally imaging a fluorescent image generated by a living tissue transmitted by an image guide. .

[0002]

2. Description of the Related Art Conventionally, there has been known a method of diagnosing tissue properties of a living body based on fluorescence generated from the living tissue by irradiating the living tissue with excitation light.

For example, a living tissue in a body cavity has a wavelength of 410 n.
m, and the yield of fluorescence expressed by the ratio of the intensity of the fluorescence generated from the living tissue by the irradiation of the excitation light to the intensity of the excitation light received by the living tissue, The tissue property of the living body is determined by an image created based on a normalized fluorescence intensity or the like represented by a ratio of the intensity of the wavelength region around 480 nm in the fluorescence generated by irradiation to the intensity of the wavelength region ranging from 430 nm to 730 nm. A fluorescent endoscope apparatus for observation has been proposed.

[0004] The above-mentioned fluorescence yield is such that when normal tissues and diseased tissues of a living body receive excitation light of the same intensity, the intensity of autofluorescence generated from normal tissues becomes higher than the intensity of autofluorescence generated from diseased tissues. Is an index for discriminating between a diseased tissue and a normal tissue on the basis of the fluorescence yield. Is used as a stable index indicating the tissue properties of the living body that are not affected by the distance and angle between the exit point for irradiating the excitation light and the measurement site of the living tissue to be irradiated with the excitation light. be able to.

In actually obtaining the fluorescence yield, it is difficult to directly measure the intensity of the excitation light received by the living tissue, and therefore, for example, light of a specific wavelength region, such as near infrared light, which is hardly absorbed by the living tissue. The intensity of the excitation light received by the living tissue is substituted by the intensity of the image of the reference light reflected by the irradiated living tissue, and the fluorescence yield is obtained.

That is, the fluorescence yield is a value determined by the ratio of the intensity of the fluorescence generated from the living tissue irradiated with the excitation light to the intensity of the excitation light irradiated to the living tissue. As an approximate value of the ratio, the intensity of the image due to the fluorescence generated from the living tissue irradiated with the excitation light and the light in a specific wavelength region (not necessarily near-infrared light, but substitute with light in the visible wavelength region) The value of the fluorescence yield is approximately determined by a value determined by a ratio of the intensity of the image with the reference light reflected by the living tissue irradiated with the above-described irradiation.

[0007] The normalized fluorescence intensity is based on the fact that the shapes of the spectra of the fluorescence generated from the normal tissue and the diseased tissue of the living body irradiated with the excitation light differ in the wavelength region near 480 nm. It is an index that is not affected by the distance, angle, and the like between the emission point for irradiating the excitation light and the measurement site of the living tissue to be irradiated with the excitation light, similarly to the fluorescence yield.

[0008] As described above, in the diagnosis of the tissue properties in the body cavity, the tissue properties of the living body are observed using the tissue property images created using the indexes such as the above-mentioned fluorescence yield and normalized fluorescence intensity. .

On the other hand, conventionally, an image of a living tissue is imaged through an elongated observation probe (sometimes called an endoscope insertion portion) inserted into a body cavity, and the obtained image is displayed on a television monitor or the like. An endoscope apparatus for observing a living tissue is known. Further, a fluorescence endoscope apparatus for spectrally measuring a fluorescence image of a living tissue in a body cavity by applying the endoscope apparatus has been studied.

[0010] For example, in a fluorescence endoscope apparatus for spectrally measuring an image due to weak fluorescent light generated from a living tissue irradiated with excitation light, an image based on the fluorescent light generated from the living tissue is used by using an image guide. The living body is guided from the end of the endoscope insertion section to the endoscope main body, and the fluorescent image guided by the image guide is spectrally captured by a high-sensitivity image sensor and displayed on a television monitor or irradiated with normal light. A normal image reflected by the tissue is captured and compared with a fluorescent image and displayed.

The image guide that propagates the fluorescent image is a bundle of tens of thousands of fibers, and the fluorescent image propagated by the image guide is such that one fiber is one pixel (called a fiber pixel). ) Is formed. On the other hand, an image sensor that captures a fluorescent image propagated by this image guide has a larger light receiving amount by reducing the number of light receiving pixels and increasing the area of the light receiving pixels in order to increase the light receiving amount per pixel. The number of light receiving pixels is about 1/10 of the number of light receiving pixels (hundreds of thousands of pixels) of the image sensor having the normal sensitivity for capturing the normal image. It is almost equal to the number of pixels.

[0012]

For this reason, the number of pixels of the high-sensitivity image pickup device for picking up a fluorescent image becomes close to the number of fiber pixels of the image guide, and the fluorescent image is formed on the image pickup surface of the high-sensitivity image pickup device. Sometimes, an image formed by fiber pixels arrayed at a constant pitch is sampled (imaged) by light receiving pixels arrayed at substantially the same pitch, and therefore does not exist in the captured image in the original fluorescent image. A regular pattern (moire) may be generated, making the image difficult to see.

[0013] Light in a specific wavelength region, that is, reference light reflected by a living tissue irradiated with light limited in a specific wavelength range is also light having a low intensity. When a high-sensitivity image sensor is used as an image sensor that captures an image with the reference light propagated by the fiber, moire occurs in the captured image as in the case of the fluorescent light, and the image becomes difficult to see. Sometimes.

An image pickup device for picking up a normal image does not need to be as sensitive as an image pickup device for picking up a fluorescent image or a reference light image. It is not.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a fluorescent endoscope capable of preventing the occurrence of moire in an image obtained by capturing an image with low light intensity transmitted by an image guide with high sensitivity. It is intended to provide a device.

[0016]

According to a first aspect of the present invention, there is provided a fluorescent endoscope apparatus comprising: an image formed by fluorescent light generated from a living tissue irradiated with excitation light; An image guide that propagates the image formed by the normal light from one end facing the living tissue to the other end, and a fluorescent image forming unit that splits and forms an image formed by the fluorescent light propagated to the other end of the image guide. A fluorescent image capturing means arranged on the optical axis of the fluorescent image forming means; a normal image forming means for forming an image by normal light propagated to the other end of the image guide; In a fluorescence endoscope apparatus provided with a normal image capturing means arranged on the optical axis of the image forming means, the normal image forming means forms an image of the normal light on an imaging surface of the normal image capturing means. And a fluorescent image forming means. Is characterized in that it is intended to form an image by the fluorescence from the imaging surface of the image means to a position shifted in the optical axis direction. That is, the focus of the image formation by the fluorescent image forming means is blurred.

The image guide propagates an image of reference light reflected by a living tissue irradiated with light in a specific wavelength region from one end facing the living tissue to the other end. Propagated to the other end of the
Reference image forming means for forming an image by reference light reflected by the living tissue irradiated with light in a specific wavelength region, and reference image imaging means arranged on the optical axis of the reference image forming means And the reference image forming means may form an image by the reference light at a position shifted in the optical axis direction from the imaging surface of the reference image imaging means.

According to a second aspect of the present invention, there is provided an image guide for transmitting an image formed by fluorescence emitted from a living tissue irradiated with excitation light from one end to the other end, and an image guide for transmitting the image to the other end of the image guide. A fluorescent endoscope apparatus comprising: a fluorescent image forming unit configured to spectrally form an image formed by the transmitted fluorescent light to form an image; and a fluorescent image forming unit configured to form an image formed by the fluorescent light formed by the fluorescent image forming unit. Wherein the fluorescent image forming means is provided with an optical low-pass filter in the optical path. That is, this is also characterized in that the focus of the image formation by the fluorescent image forming means is out of focus.

A third fluorescence endoscope apparatus according to the present invention comprises an image formed by fluorescence generated from a living tissue irradiated with excitation light and a reference light reflected by the living tissue irradiated with light in a specific wavelength region. An image guide that propagates an image by light from one end facing the living tissue to the other end, and a fluorescence image forming unit that spectrally forms an image by the fluorescence transmitted to the other end of the image guide and forms the image. A fluorescent image imaging means arranged on the optical axis of the fluorescent image forming means, a reference light image forming means for forming an image by the reference light propagated to the other end of the image guide, and the reference light image In a fluorescence endoscope apparatus comprising: a reference light image capturing means arranged on the optical axis of the imaging means;
Reference light image forming means and fluorescent image forming means, in the optical path,
It is characterized by having an optical low-pass filter.

It is preferable that the light in the specific wavelength region is light in a near infrared region on a longer wavelength side than 700 nm.

The fluorescent image forming means forms an image of fluorescence separated into two or more wavelength regions different from each other, and the fluorescent image capturing means forms an image by the fluorescent image forming means. In addition, an image of each fluorescence can be taken.

The normal light means light having a wavelength in the visible region.

The light in the specific wavelength region means light having a low intensity limited to a predetermined wavelength range.

To form an image on the imaging surface means that an image that is accurately focused is formed on the imaging surface.

Further, to form an image at a position shifted in the optical axis direction from the imaging surface means that an image due to the fluorescent light propagated to the end face of the image guide is separated from the imaging surface in the optical axis direction by a distance that can prevent the occurrence of moire. Means that the image is formed at the position where it is located.

[0026]

According to the first fluorescent endoscope apparatus of the present invention, an image formed by the ordinary light is formed on the imaging surface of the normal image pickup means, while an image formed by the fluorescent light or the image formed by the reference light is a fluorescent image. Since the image is formed at a position shifted in the optical axis direction from the imaging surface of the imaging means, the normal image is imaged in focus, while the image by the fluorescent light or the image by the reference light is blurred. It is possible to prevent the occurrence of moire in the captured fluorescent image. Because the fluorescence image or the reference light image on the imaging surface of the fluorescence image imaging means is out of focus, an image in which a component having a high spatial frequency is attenuated, and pixels between pixels arranged at the same pitch as the light receiving pixels. This is because an image having a boundary is not sampled, so that occurrence of moire in an image obtained by capturing a fluorescent image or a reference light image can be prevented.

According to the second and third fluorescent endoscope apparatuses of the present invention, since the optical low-pass filter is provided in the optical path of the fluorescent image forming means or the reference light image forming means, the fluorescent image is formed. Alternatively, the intensity of the image due to the high spatial frequency fiber pixel included in the reference light image is attenuated, and the fiber pixel is not sampled as an image having a boundary between pixels arranged at the same pitch as the light receiving pixel, It is possible to prevent occurrence of moire in an image obtained by capturing a fluorescent image or a reference light image.

Further, when the light in the specific wavelength region is light in the near-infrared region on the longer wavelength side than 700 nm, the absorption by the living tissue is small, and the intensity of the light in the specific wavelength region irradiated on the living tissue can be more accurately determined. (I.e., reference light) can be obtained.

It should be noted that the fluorescent image forming means is provided with two different fluorescent image forming means.
It is assumed that images of fluorescence separated in one or more wavelength regions are formed, and that the fluorescence image capturing means captures images of the respective fluorescences formed by the fluorescent image forming means. Images of a plurality of fluorescences separated into different wavelength bands can be captured, and this allows calculation between the captured fluorescence images to be performed. Therefore, it is possible to obtain an index such as normalized fluorescence intensity. it can.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a fluorescence endoscope apparatus according to a first embodiment of the present invention, and FIG. 2 shows fiber pixels of a regularly arranged image guide and light receiving pixels of a high-sensitivity image sensor. FIG. The fluorescence endoscope apparatus according to the first embodiment is configured to prevent the occurrence of moiré by forming a fluorescent image at a position shifted in the optical axis direction from the imaging surface of the high-sensitivity image sensor. It is a thing.

The fluorescence endoscope apparatus 100 according to the first embodiment of the present invention provides an image Zk of the fluorescence generated from the living tissue 1 irradiated with the excitation light Le emitted from the light source 10.
And an image guide for propagating an image Zt of the normal light reflected by the living tissue 1 irradiated with the normal light Lt emitted from the same light source from one end face 21A at one end facing the living tissue 1 to an end face 21B at the other end. 21, fluorescent image forming means 30 for spectrally forming the fluorescent image Zk propagated to the end face 21B of the image guide 21, and forming a fluorescent image imaging means arranged on the optical axis of the fluorescent image forming means 30; Sensitivity image sensor 4
1, 42 and 43, end surface 21B of image guide 21
Image forming means 5 for forming the normal image Zt transmitted to the
0, and a normal image pickup element 61 which is a normal image pickup means for picking up a normal image formed by the normal image formation means 50
It has.

The fluorescent image forming means 30 separates the fluorescent image Zk into three different wavelength regions and separates the fluorescent image Zk into three spectral fluorescent images Zk1, Zk2 and Zk3 on three optical paths. High sensitivity imaging elements 41, 42 and 43
Are arranged on the optical axis of each optical path for forming the spectral fluorescence images Zk1, Zk2, and Zk3. Each of the high-sensitivity image sensors 41, 42, and 43 has tens of thousands of light receiving pixels, which are almost the same as the number of fiber pixels of the image guide, and the normal image imaging device 61 has hundreds of thousands of light receiving pixels.

The image guide 21 and the light guide 22 for transmitting the excitation light Le and the normal light Lt emitted from the light source 10 are disposed inside the endoscope insertion section 20 inserted into the body cavity. .

The normal image forming means 50 includes an objective lens 34 for forming a primary image of the normal image Zt propagated to the end face 21B of the image guide, a switching mirror 39 for reflecting normal light propagated through the objective lens 34 at right angles, A reflecting mirror 51 for reflecting the normal light reflected by the switching mirror 39 at a further right angle; and an imaging lens 52 for forming the normal light reflected by the reflecting mirror 51 as a normal image Zt1. 39 is shared with the fluorescent image forming means 30.

The switching mirror 39 switches the optical paths of the normal light and the fluorescent light by rotating the one end O by 45 degrees, and reflects the normal light incident through the objective lens 34 in the direction of the reflecting mirror 51. In the case where the fluorescent light is disposed at an angle of 45 degrees with respect to the optical axis and inserted into the optical path, and when the fluorescent light incident through the objective lens 34 is propagated in the direction of a dichroic mirror 35 described later, with respect to the optical axis, They are arranged in a parallel orientation and are removed from the optical path.

The fluorescent image forming means 30 has the above-mentioned three branched optical paths, and the first optical path for forming the spectral fluorescent image Zk1 has the fluorescent image Zt transmitted to the end face 21B of the image guide. Objective lens 34 for producing a primary image, objective lens 34
A dichroic mirror 35 for transmitting and reflecting the fluorescence transmitted through the dichroic mirror 35, an imaging lens 31 for forming the fluorescent light transmitted through the dichroic mirror 35 as a spectral fluorescent image Zk1, and the fluorescent light reflected by the dichroic mirror 35. The second optical path for imaging the spectral fluorescence image Zk2 to be propagated includes a half mirror 36 that transmits and reflects light to branch the optical path, and only fluorescent light of a specific wavelength region in the fluorescent light reflected by the half mirror 36. A third bandpass filter 37A for transmitting light, and an imaging lens 32 for forming fluorescent light transmitted through the bandpass filter 37A as a spectral fluorescent image Zk2, and forming a spectral fluorescent image Zk3 for transmitting fluorescent light transmitted through the half mirror 36. In the optical path, light of a specific wavelength region different from the bandpass filter 37A is transmitted. Band filter 37B that transmits,
A reflection mirror 38 that reflects the fluorescence transmitted through the bandpass filter 37B and an imaging lens 33 that forms the fluorescence reflected by the reflection mirror 38 as a spectral fluorescence image Zk3 are provided.

The image data processing circuit 72 inputs image data representing a normal image picked up and output by the normal image pickup device 61, converts the image data into a video signal, and outputs the video signal. Image data representing the captured and output spectral fluorescence images Zk1, Zk2, and Zk3 is input, and each image data is converted into a video signal and output individually, or the result of performing an operation between these image data is obtained. They are converted into video signals and output. The video signal representing the normal image output from the image data processing circuit 72 is displayed on the display 73, and the video signal representing the spectral fluorescence image is displayed on the display 74.

It should be noted that the normal image Zt is formed on the image pickup surface of the normal image pickup device 61, and the spectral fluorescent images Zk1 and Zk1 are shifted from the image pickup surfaces of the high-sensitivity image pickup devices 41, 42 and 43 in the optical axis direction. The positioning of each optical element for imaging Zk2 and Zk3 is performed by the following method.

In the first positioning method, first, the normal image pickup element 61 is moved in the direction of the optical axis while observing the image picked up by the normal image pickup element 61 and displayed on the display 73, and is displayed. By focusing the normal image Zt1, the imaging plane of the normal image imaging element 61 is made to coincide with the imaging plane of the normal image Zt1. Next, the high-sensitivity image sensor 41
Fluorescent image Z imaged by the camera and displayed on the display 74
By moving the high-sensitivity image sensor 41 in the optical axis direction while observing the image of k1 and focusing the displayed spectral fluorescent image Zk1, the high-sensitivity image sensor 41 captures an image on the imaging plane of the spectral fluorescent image Zk1. Match the faces. Similarly, by focusing the spectral fluorescent images Zk2 and Zk3 displayed on the display 74, the spectral fluorescent images Zk2 and Zk3 are focused.
The imaging planes of the high-sensitivity imaging elements 42 and 43 are matched with the imaging plane 3. At this time, moire occurs in the spectral fluorescence images Zk1, Zk2, and Zk3 displayed on the display 74.

That is, the end surface 21 of the image guide 21
B is composed of a large number of regularly arranged fiber pixels as shown in FIG.
On the imaging surface of the high-sensitivity image sensor that captures the spectral fluorescence image propagated to B, light-receiving pixels arranged regularly as shown in FIG. Therefore, when the spectral fluorescence image including the image of the fiber pixel is formed on the imaging surface of the high-sensitivity imaging device and imaged, the images representing the fiber pixels arranged at a constant pitch are arranged at the same pitch. Moire occurs because the light receiving pixels are sampled.

Next, the objective lens 3 is observed while observing the image of each spectral fluorescence image including the moiré displayed on the display 74.
4 is moved in the optical axis direction, and the imaging positions of the three spectral fluorescence images are simultaneously moved. After moving the imaging position of the spectral fluorescent image so that moire is removed from the displayed image representing each spectral fluorescent image, the objective lens 34 is fixed.

In order to remove moiré in an image, it is sufficient that fiber pixels arranged at a constant pitch are not sampled. Therefore, the spectral fluorescence image is shifted from the imaging surface of the high-sensitivity imaging device in the optical axis direction. The fiber pixels are imaged in a blurred state, as shown in FIG. 3, so that the fiber pixels are sampled as images arranged at a constant pitch. Moiré can be prevented from occurring. At this time, the position of the normal image Zt1 is also moved in the optical axis direction, and the normal image displayed on the display 73 is also an out-of-focus image.

Thereafter, the position of the imaging lens 52 or the normal image pickup device 61 is adjusted so that the image formation surface of the normal image Zt1 and the image pickup surface of the normal image pickup device 61 match.

As a result, the display 74 displays a spectral fluorescence image from which moire has been removed, and the display 73 displays a focused normal image.

In the second positioning method, first, similarly to the first positioning method, the imaging surface of the normal image pickup element 61 is made to coincide with the imaging surface of the normal image Zt1, and the spectral fluorescence images Zk1 and Zk2 And the imaging planes of the high-sensitivity imaging elements 41, 42, and 43 match the imaging planes of Zk3. At this time, the spectral fluorescence images Zk1 and Zk displayed on the display 74 are displayed.
Moire occurs in 2 and Zk3 for the same reason as described above.

Next, while observing the spectral fluorescence image Zk1 in which the moire has occurred displayed on the display 74, the high-sensitivity image sensor 41 is moved in the optical axis direction until moire is removed from the displayed image. Let it. Similarly, regarding the spectral fluorescence images Zk2 and Zk3 in which moire has occurred, the high-sensitivity image sensors 42 and 43 are respectively moved in the optical axis direction until moire is removed from the displayed image.

As a result, the occurrence of moire can be prevented for the same reason as described above. The display 74 displays a spectral fluorescent image from which moire has been removed, and the display 73 displays a focused normal image. Is displayed.

Next, the operation of the first embodiment will be described.

First, in order to observe a normal image of the living tissue 1, the switching mirror 39 is inserted into the optical path at an angle. Next, the living tissue 1 is irradiated with the normal light Lt emitted from the light source 10 through the light guide 22 and the irradiation lens 23. The normal image Zt by the normal light reflected by the living tissue 1 irradiated with the normal light is transmitted to the end face 21B through the incident lens 24 and the image guide 21. The normal image Zt propagated to the end surface 21B of the image guide is reflected by the switching mirror 39 and the reflection mirror 51, and forms a normal image Zt1 on the imaging surface of the normal image imaging device 61 through the objective lens 34 and the imaging lens 52. Imaged. The normal image Zt1 formed on the imaging surface of the normal image imaging device 61 is imaged by the normal image imaging device 61 and output as image data, and then converted into a video signal by the image data processing circuit 72 and displayed on the display 73. Is displayed.

Next, the switching mirror 39 is removed from the optical path in order to observe the spectral fluorescence image of the living tissue 1, and the excitation light Le emitted from the light source 10 is irradiated on the living tissue 1 through the light guide 22 and the irradiation lens 23. . The fluorescence image Zk generated from the living tissue 1 irradiated with the excitation light Le passes through the incident lens 24 and the image guide 21 and the end face 2 thereof.
1B. Fluorescent image Zk propagated to end face 21B
Are separated into three wavelength regions different from each other and are formed as spectral fluorescence images Zk1, Zk2, and Zk3 at positions shifted in the optical axis direction from the imaging surfaces of the high-sensitivity imaging elements 41, 42, and 43, respectively. These spectral fluorescence images Zk1,
Zk2 and Zk3 are high-sensitivity image sensors 41, 42, 43
After being picked up and output as image data, the image data is converted into a video signal by the image data processing circuit 72 and displayed on the display 74.

Here, the high-sensitivity image sensors 41, 42, 43
And the positions of the imaging planes of the respective spectral fluorescent images Zk1, Zk2, and Zk3 formed by the fluorescent image forming means 30 are set in advance in the optical axis direction by a distance that does not cause moire in the captured image. , The occurrence of moiré in the image displayed on the display 74 can be prevented. By switching the switching mirror 39, each of the spectral fluorescent images from which moiré has been removed and the normal image in focus Can be selected and displayed, and the two images can be compared and observed.

Each spectral fluorescence image is picked up and displayed as an out-of-focus image. However, since the image generated by the fluorescent light generated from the living tissue does not originally have a clear outline, it can be observed even if the image is slightly out of focus. There are few problems in doing so.

Further, the image data processing circuit 72 performs an operation between the image data to determine the ratio of the intensity between the respective spectral fluorescent images spectrally dispersed in a specific wavelength region, and appropriately adjusts the characteristics of the dichroic mirror, the band-pass filter and the like. Observe the more detailed tissue properties of the living body as a visible image by selecting and calculating the value obtained by dividing the intensity of the fluorescent image in the specific wavelength region by the intensity of the fluorescent image over the entire wavelength region, that is, obtaining the normalized fluorescent intensity. You can also do so.

Further, as shown in FIG. 4, the light source arranged in the above embodiment is changed to a light source 10 'which can irradiate near-infrared light Lk in a specific wavelength region together with excitation light Le and normal light Lt. And near-infrared light L from the light source 10 ′ between the switching mirror 39 and the dichroic mirror 35.
The near-infrared light (reference light image Zs) reflected by the living tissue 1 irradiated with s is reflected, and light in a wavelength region shorter than near-infrared, that is, a wavelength region containing fluorescence generated from the living tissue is transmitted. The reference light image Zs is extracted by arranging the dichroic mirror 91 to be made, and the reference light image Zs is reflected at a right angle by the reflection mirror 92 to form the imaging lens 9.
By forming the reference light image Zs1 at a position shifted in the optical axis direction from the imaging surface of the high-sensitivity image sensor 94 by 3, an image by the reference light from which moire has been removed is picked up by the high-sensitivity image sensor 94 in the same manner as described above. can do. The imaged reference light image is output as image data from the high-sensitivity image sensor 94, and the image data processing circuit 72 'performs an operation between the images acquired. For example, fluorescence generated from living tissue by irradiation with excitation light And the intensity of the excitation light received by the living tissue (in the above-described embodiment, the intensity of the image by the reference light) is calculated. More detailed tissue properties can be observed as a visible image.

FIG. 5 is a block diagram showing a schematic configuration of a fluorescence endoscope apparatus according to the second embodiment of the present invention. In the fluorescence endoscope apparatus according to the second embodiment, a phase plate 81 such as a crystal birefringent plate, which is an optical low-pass filter, is inserted between the switching mirror 39 and the dichroic mirror 35, and the phase plate 81 is transmitted therethrough. By doing so, two spectral fluorescence images separated by birefringence are formed on the imaging surface of the high-sensitivity imaging device, and the other configuration is the same as that of the first embodiment. Become. Hereinafter, the same components as those of the fluorescence endoscope apparatus according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

Switching mirror 39 similar to that of the first embodiment.
The operation of observing the normal image of the living tissue 1 by inserting the tilted light into the optical path is omitted, and the operation of observing the spectral fluorescence image of the living tissue 1 by removing the switching mirror 39 from the optical path will be described.

A fluorescent image Zk due to the fluorescence generated from the living tissue 1 irradiated with the excitation light Le emitted from the light source 10
Is transmitted to the end face 21B through the incident lens 24 and the image guide 21. The fluorescent image Zk propagated to the end face 21B is separated into two spectral fluorescent images by transmitting through the phase plate 81, and further separated into three different wavelength regions to be imaged by the high-sensitivity image sensors 41, 42, and 43. Each image is formed on a plane. The three sets of spectral fluorescence images spectrally formed and formed in the three wavelength regions are high-sensitivity image sensors 41 and 4.
Image data processing circuit 72 imaged by 2 and 43
Is displayed on the display 74 through the.

Here, the two spectral fluorescence images which are separated by birefringence are overlapped and formed on the imaging surface of each high-sensitivity imaging device, so that an image having a high spatial frequency is out of focus. Since the intensity is attenuated, the image due to the boundary between the fiber pixels is attenuated, and the occurrence of moire can be prevented. Other operations are the same as those of the first embodiment.

As an optical low-pass filter,
Not limited to the crystal birefringent plate, a transparent plastic phase grating or the like having a cross-sectional surface shape such as a rectangular wave or a sawtooth wave may be used.

FIG. 6 is a block diagram showing a schematic configuration of a fluorescence endoscope apparatus according to the third embodiment of the present invention. The fluorescence endoscope apparatus according to the third embodiment is an apparatus configured to capture a fluorescence image and a reference light image that is light in a specific wavelength region without capturing a normal image. The fluorescence endoscope apparatus includes a light source 10 ″ that emits excitation light Le and near-infrared light Ls that is light in a specific wavelength region, and an image guide that is reflected by the living tissue 1 irradiated with the near-infrared light Ls. A reference light image forming means 5 for forming a reference light image Zs propagated on the end face 21B of the reference numeral 21
0 ', and a high-sensitivity image sensor having tens of thousands of light receiving pixels on the optical axis of the optical path on which the reference light image Zs1 is formed by the reference light image forming means 50', which is approximately the same as the number of fiber pixels of the image guide. 61 'is provided.

The reference light image forming means 50 'is an objective lens 34' for forming a primary image of the reference light image Zs propagated to the end face 21B of the image guide, and reflects the reference light propagated through the objective lens 34 'at right angles. And a dichroic mirror 3 for transmitting the fluorescence transmitted through the objective lens 34 '.
9 ', a reflecting mirror 51' for reflecting the reference light reflected by the dichroic mirror 39 'at a right angle, and a reference image Zs for reflecting the reference light reflected by the reflecting mirror 51'.
An imaging lens 52 'for forming an image as 1 and a phase plate 81' such as a crystal birefringent plate as an optical low-pass filter are provided in an optical path between the dichroic mirror 39 'and the reflection mirror 51'.

The other structure is the same as that of the second embodiment. Hereinafter, the same components as those of the fluorescence endoscope apparatus according to the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

Next, the operation when observing the reference light image of the living tissue 1 will be described. The operation of observing the fluorescent image of the living tissue 1 as in the second embodiment is omitted.

The living tissue 1 is irradiated with the near-infrared light Ls emitted from the light source 10 ″ through the light guide 22 and the irradiation lens 23. The reference light reflected by the living tissue 1 irradiated with the near-infrared light Ls The reference light image Zs is incident on the end face 21 through the incident lens 24 and the image guide 21.
Propagated to B. The reference light image Zs propagated to the end surface 21B of the image guide is reflected by the dichroic mirror 39 'and the reflection mirror 51' and passes through the objective lens 34 'and the imaging lens 52', and the imaging surface of the high-sensitivity imaging device 61 '. The image is formed as a reference light image Zs1 on the upper side.

Here, when the reference image Zs propagated to the end face 21B of the image guide propagates through the phase plate 81 'arranged in the optical path between the dichroic mirror 39' and the reflection mirror 51 '. The two reference light images which are birefringent and slightly separated from each other are formed so as to overlap on the imaging surface of the high-sensitivity imaging device 61 '. As a result, the image with a high spatial frequency is out of focus, and the intensity is attenuated. Therefore, the image due to the boundary between the fiber pixels is attenuated, and the occurrence of moire can be prevented.

The reference light image Zt1 formed on the imaging surface of the high-sensitivity image sensor 61 'is picked up by the high-sensitivity image sensor 61' and output as image data to the image data processing circuit 71 '. For example, the ratio 72 represents the ratio of the intensity of the image due to the fluorescence generated from the living tissue by the irradiation of the excitation light to the intensity of the excitation light received by the living tissue (in the above embodiment, the intensity of the image due to the reference light). The values such as the fluorescence yield to be obtained are obtained, and an image representing the tissue properties of the living tissue is displayed. For other actions,
This is the same as the second embodiment.

The above-mentioned image pickup device (including a high-sensitivity image pickup device) is a CCD type image pickup device or a MOS type image pickup device.
Any type of image sensor may be used as long as the image sensor has pixels.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a fluorescence endoscope apparatus according to a first embodiment.

FIG. 2 is an enlarged view showing regularly arranged fiber pixels and light receiving pixels.

FIG. 3 is a diagram showing an image of a fiber pixel captured in an out-of-focus state;

FIG. 4 is a diagram showing a schematic configuration of a fluorescence endoscope apparatus to which a function of capturing a reference light image is added.

FIG. 5 is a diagram illustrating a schematic configuration of a fluorescence endoscope apparatus according to a second embodiment of the present invention;

FIG. 6 is a diagram showing a schematic configuration of a fluorescence endoscope apparatus according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Living tissue 10 Light source 20 Endoscope insertion part 21 Image guide 30 Fluorescent image imaging means 39 Switching mirror 41,42,43 High-sensitivity imaging device 50 Normal image imaging means 61 Normal image imaging device 73,74 Display 81 Phase Board

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Claims (6)

[Claims] 1. An image formed by fluorescence generated from a living tissue irradiated with excitation light and an image formed by normal light reflected by the living tissue irradiated with normal light are applied to one end of the living tissue facing the living tissue. An image guide that propagates to the edge,
Fluorescent image forming means for spectrally forming an image of the fluorescence transmitted to the other end of the image guide to form an image, fluorescent image capturing means arranged on an optical axis of the fluorescent image forming means, A fluorescent endoscope comprising: a normal image forming means for forming an image by the normal light propagated to the other end of the guide; and a normal image capturing means arranged on an optical axis of the normal image forming means. In the apparatus, the normal image forming means forms an image of the normal light on an imaging surface of the normal image capturing means, and the fluorescent image forming means captures an image of the fluorescent image capturing means. A fluorescent endoscope apparatus for forming an image by the fluorescent light at a position shifted from the surface in the optical axis direction. 2. The image guide, wherein an image by reference light reflected by the living tissue irradiated with light in a specific wavelength region propagates from one end facing the living tissue to the other end, Reference image forming means for forming an image by reference light reflected by the living tissue irradiated with the light of the specific wavelength region and propagated to the other end of the image guide; and the reference image forming means. And a reference image imaging unit disposed on the optical axis of the reference image forming unit, wherein the reference image forming unit forms the reference image at a position shifted from the imaging surface of the reference image imaging unit in the optical axis direction. The fluorescence endoscope apparatus according to claim 1, wherein 3. An image formed by fluorescence generated from a living tissue irradiated with excitation light and an image formed by normal light reflected by the living tissue irradiated with normal light are applied to one end of the living tissue facing the living tissue. An image guide that propagates to the edge,
Fluorescent image forming means for spectrally forming an image of the fluorescence transmitted to the other end of the image guide to form an image, fluorescent image capturing means arranged on an optical axis of the fluorescent image forming means, A fluorescent endoscope comprising: a normal image forming means for forming an image by the normal light propagated to the other end of the guide; and a normal image capturing means arranged on an optical axis of the normal image forming means. In the apparatus, the normal image forming means forms an image by the normal light on an imaging surface of the normal image capturing means, and the fluorescent image forming means includes an optical low-pass in an optical path. A fluorescence endoscope apparatus comprising a filter. 4. An image formed by fluorescence generated from living tissue irradiated with excitation light and an image formed by reference light reflected by the living tissue irradiated with light in a specific wavelength region are exposed to the living tissue. An image guide that propagates from one end to the other end, a fluorescent image forming unit that splits and forms an image of the fluorescent light that has propagated to the other end of the image guide, and a fluorescent image forming unit on the optical axis of the fluorescent image forming unit. A fluorescent light image pickup means, a reference light image forming means for forming an image by the reference light propagated to the other end of the image guide, and a fluorescent light image pickup means disposed on the optical axis of the reference light image forming means. A fluorescence endoscope apparatus comprising: a reference light image imaging unit; and the reference light image forming unit and the fluorescence image forming unit are provided with an optical low-pass filter in an optical path. Fluorescent endoscope device. 5. The fluorescence endoscope apparatus according to claim 2, wherein the light in the specific wavelength region is a light in a near-infrared region longer than 700 nm. 6. The apparatus according to claim 1, wherein said fluorescent image forming means comprises two different fluorescent image forming means.
Forming an image of the fluorescence dispersed in one or more wavelength regions, wherein the fluorescent image capturing unit captures an image of each fluorescent light formed by the fluorescent image forming unit. The fluorescence endoscope apparatus according to any one of claims 1 to 5, wherein: